WO2019071917A1

WO2019071917A1 - Satellite tracking method

Info

Publication number: WO2019071917A1
Application number: PCT/CN2018/080033
Authority: WO
Inventors: 杨飞; 袁世钊; 刘冰; 吴晓文
Original assignee: 深圳市华讯方舟空间信息产业科技有限公司; 华讯方舟科技有限公司
Priority date: 2017-10-12
Filing date: 2018-03-22
Publication date: 2019-04-18
Also published as: CN107783156A; CN107783156B

Abstract

A satellite tracking method, which is used for the fast tracking and alignment of satellites, comprising: acquiring a directional coefficient function of an antenna (S100); acquiring a Jacobian matrix of the directional coefficient function, the Jacobian matrix being used for determining a direction of angle compensation for the antenna (S200); acquiring a deviation angle matrix of the antenna relative to a satellite by means of scanning, the deviation angle matrix being used for providing a function model in order to acquire a compensation angle (S300); acquiring the compensation angle according to the directional coefficient function, the deviation angle matrix and the Jacobian matrix, the compensation angle being used for guiding the antenna to move at a next moment; dynamically acquiring the compensation angle and continuously adjusting the antenna according to the compensation angle during a process of alignment so as to scan, track and align the satellite (S500). A satellite tracking error is rapidly converged by means of acquiring less or lower-frequency beam signal data, thus implementing high-precision satellite alignment.

Description

Satellite tracking method

Technical field

The present invention relates to the field of electromagnetic beam tracking, and in particular to a satellite tracking method.

Background technique

High-precision acquisition and tracking of satellite signals has always been a core indicator of satellite antennas. Most of the current methods of automatic tracking satellites involve hardware analysis of satellite signal power level values rssi for beam signal indication. The current satellite tracking algorithm is a simple processing of the satellite beam signal value. By stepping the vicinity of the incoming beam and searching for the maximum point of the signal, as a star-based basis, the signal processing method is very simple. There is a large delay, the error is also large, and the precision needs to be improved.

Moreover, the partial scanning method is only based on the way of finding the maximum signal position. This processing mechanism has no problem for single-sided reception, but there is also a shortage for antenna transmission, because the antenna transmission and reception main lobe cannot be guaranteed during antenna design and installation. The axes are completely coincident, and the inconsistent transmission and reception frequency points also cause the directivity coefficient function of the transmitting and receiving beams to be inconsistent. If the received signal strength is simply analyzed, the transmission beam pattern characteristics will be affected, and the transmission gain performance and the cross polarization isolation will be affected.

Summary of the invention

Based on this, it is necessary to provide a satellite tracking method for problems such as low precision, large error, and delay.

A satellite tracking method for achieving fast alignment of satellites, including:

Obtaining a directivity coefficient function of the antenna;

Obtaining a Jacobian matrix of the directivity coefficient function, wherein the Jacobian matrix is used to determine an angle compensation direction of the antenna;

Obtaining, by scanning, a matrix of deviation angles of the antenna relative to a satellite, the deviation angle matrix being used to provide a function model for acquiring a compensation angle;

Obtaining the compensation angle according to the directivity coefficient function, the deviation angle matrix, and the Jacobian matrix, wherein the compensation angle is used to guide the antenna to move at a next moment;

The compensation angle is dynamically acquired during the alignment process, and the antenna scan tracking alignment satellite is continuously adjusted according to the compensation angle.

In one embodiment, the step of acquiring a directivity coefficient function of the antenna includes:

Collecting direction coefficient data of different frequency bands of the antenna;

Converting the direction coefficient data of the different frequency bands to generate far-field direction coefficient data;

A fitting function model fitting corresponding to the antenna is selected according to the far field direction coefficient data to generate a directivity coefficient function.

In one embodiment, the step of collecting direction coefficient data of different frequency bands of the antenna includes:

Collect the direction coefficient data of the antenna receiving band and the transmitting band.

In one of the embodiments, for a planar array antenna, the fit function model is:

Where J ₁ (x) is a first-order Bessel function,

u=[Az El],

Az is the azimuth difference of the antenna obtained by the actual measurement of the antenna microwave darkroom; El is the difference of the pitch angle of the antenna obtained by the actual measurement of the antenna microwave darkroom; h is a constant, which is automatically generated by function fitting;

Substituting the azimuth difference value Az and the pitch angle difference value El into the function model to obtain a directivity coefficient function D(Az, El);

For a reflector antenna, the fit function model is:

Where J ₁ (x) is a first-order Bessel function, x=u; u=[Az El];

Substituting the azimuth difference value Az and the pitch angle difference value E of the antenna into the function model yields a directivity coefficient function D(Az, El).

In one embodiment, the obtaining a Jacobian matrix of the directivity coefficient function, the Jacobian matrix is used for determining an angle compensation direction of the antenna, comprising:

Said

among them,

Where D(Δθ _n ) is another representation of D(Az, El).

In one embodiment, the obtaining, by scanning, a matrix of deviation angles of the antenna relative to a satellite, the deviation angle matrix being used to provide a function model for obtaining a compensation angle, comprising:

Obtaining the actual azimuth difference Az and the elevation angle difference El of the antenna by scanning measurement,

Then Δθ satisfies:

among them,

For the angular angular velocity matrix,

It is the derivative of Δθ versus time; H=ωK, H is a constant coefficient; where Gk(rssi) is a function of the scan range, and the size is determined by the value of the antenna beam signal value rssi; K _Az and K _El are the scan scale coefficients.

In one of the embodiments, the scan range function Gk(rssi) is based on the PI filter principle:

Is a constant; rssi _n and rssi _k respectively represent the collected values of the nth and kth rssi; Kp is a proportional amplification factor; Ki is an integral amplification factor;

Among them, the spiral progressive scan is performed by automatically changing the size of the scan range value of the scan range function.

In one embodiment, the acquiring the compensation angle according to the directivity coefficient function, the deviation angle matrix, and the Jacobian matrix, the compensation angle is used to guide the antenna to move at a next moment. Steps, including:

The compensation angle

among them,

For the calculated intermediate variable; Δθ _n-1 is the deviation angle matrix value at time n-1; rssi _n is the collected value of the nth rssi;

It is a Jacobian matrix; D(Az, El) is the actual directivity coefficient function; Δt is the algorithm iteration period; β is the adjustment step size, and the values of different types of antennas β are different.

In one embodiment, the step of dynamically acquiring the compensation angle during the alignment process and continuously adjusting the antenna scan tracking alignment satellite according to the compensation angle includes:

And continuously adjusting the azimuth difference value Az and the pitch angle difference value of the antenna according to the compensation angle; the spiral progressive scan tracking alignment satellite;

Wherein, the spiral progressive scan is performed by automatically changing the size of the scan range value of the scan range function,

The scan range function Gk(rssi) is based on the principle of the PI filter:

Where Gk _n represents the output value of the nth Gk(rssi) function, ie the scan range value; rssi _max is a theoretically calculated value, which is a constant; rssi _n and rssi _k represent the nth and kth rssi respectively Collected value; Kp is a proportional amplification factor; Ki is an integral amplification factor;

Wherein, whether the satellite is aligned is determined by a signal quality indicator of the satellite receiver.

The above satellite tracking method quickly converges the satellite tracking error by collecting less or lower frequency beam signal data, and continuously tracks the alignment satellite by continuously obtaining the compensation angle, thereby improving the accuracy of satellite alignment and the accuracy of beam tracking, and reducing Delay and error. At the same time, it can be well adapted to the needs of various satellite beam tracking. Make full use of existing hardware condition resources without adding additional equipment, which reduces the dependence on the accuracy of servo drive system and attitude inertial navigation system.

DRAWINGS

1 is a flow chart of a satellite tracking method in an example;

2 is a flow chart of obtaining a directivity coefficient function of an antenna in an embodiment.

Detailed ways

The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It is understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

1 is a flow chart of a satellite tracking method according to an embodiment. The satellite tracking method is used to implement fast tracking alignment of satellites, and includes the following steps S100-S500.

In step S100, a directivity coefficient function of the antenna is obtained.

The directivity coefficient of the antenna is used to indicate the degree of concentrated radiation of the antenna, and is specifically defined as the ratio of the radiated power density of the antenna in the maximum radiation direction to the radiated power density of the uniform radiation in the direction in the case where the total radiated power is the same. The directivity coefficient of the antenna is actually the directivity coefficient function of the antenna. Firstly, according to different antenna types, the theoretical calculation is carried out, and the direction pattern data of the antenna obtained by the antenna microwave darkroom test is combined, and the obtained direction pattern data is synthesized into a pattern by the averaging method. A regression fit is applied to the pattern to generate a directivity coefficient function.

As shown in FIG. 2, in one embodiment, a process for generating a directivity coefficient function of an antenna includes:

Step S110, collecting direction coefficient data of different frequency bands of the antenna.

Specifically, in an embodiment, the directional coefficient data of the antenna receiving frequency band and the transmitting frequency band are collected.

For example, for the ka satellite antenna, it is assumed that the receiving frequency band is 18.7 to 19.2, and the transmitting frequency band is 29.5 to 30.0. 10 frequency points are extracted from the medium interval in the receive band. Extract 10 frequency points from the medium interval in the transmit band. The 20 sets of pattern data corresponding to the 20 frequency points are respectively collected in the antenna microwave darkroom. Of course, this collection method is not limited, and data acquisition can be performed on different satellite antennas according to actual operations and needs.

Step S120, converting direction coefficient data of the different frequency bands to generate far-field direction coefficient data.

Specifically, in an embodiment, the collected direction coefficient data of the antenna receiving frequency band is converted to generate far-field direction coefficient data; and the direction coefficient data of the collected antenna transmitting frequency band is converted to generate far-field direction coefficient data.

Step S130, selecting a fitting function model corresponding to the antenna to generate a directivity coefficient function according to the far field direction coefficient data.

Specifically, in one embodiment, for a planar array antenna, the fitting function model is:

Where J ₁ (x) is a first-order Bessel function, and Bezier function J _α (x) is a general term for a class of special functions in mathematics. The Bessel function is the solution of the Bessel equation. Usually the single-bessel function refers to the first type of Bessel function. The concrete form of the Bessel function varies with any real number α in the Bessel equation (correspondingly, α is called the order of its corresponding Bessel function). The most common case in practical applications is that α is an integer n and the corresponding solution is called an n-order Bessel function. J ₁ (x) is the solution of the corresponding Bessel equation when n is 1.

Here, in the Bessel function

u is a one-dimensional array containing two angle values, one H-direction deviation angle, and one V-direction deviation angle.

Wherein, Az is the azimuth difference value of the antenna obtained by the actual measurement of the antenna microwave darkroom; El is the difference of the pitch angle of the antenna obtained by the actual measurement of the antenna microwave darkroom; h is a constant, which is automatically generated by function fitting;

Substituting the azimuth difference value Az and the pitch angle difference value El into the function model yields a directivity coefficient function D(Az, El), and D(Az, El) is a two-input function.

For a reflector antenna, the fit function model is:

Where J ₁ (x) is a first-order Bessel function, x=u; u=[Az El]; u is a one-dimensional array containing two angular values, one H-direction deviation angle, and one V-direction deviation angle. This can be understood as u=[Az El],

Substituting the azimuth difference Az and the pitch angle difference E of the antenna into the function model yields a directivity coefficient function D(Az, El), which is a two-input function.

Step S200: Acquire a Jacobian matrix of the directivity coefficient function, and the Jacobian matrix is used to determine an angle compensation direction of the antenna.

Specifically, the obtained directional coefficient function is subjected to partial differential derivation to obtain a Jacobian matrix, and the Jacobian matrix can be obtained by the following formula:

Said

among them,

Where D(Az, El) is the actual direction coefficient function generated by the simulation, and D(Δθ _n ) is another representation of D(Az, El). It can be understood that D(Δθ _n )=D(Az, El ).

Step S300, obtaining, by scanning, a matrix of deviation angles of the antenna with respect to a satellite, wherein the deviation angle matrix is used to provide a function model for acquiring a compensation angle.

Specifically, in an embodiment, a matrix of deviation angles of the antenna relative to a satellite is obtained by scanning, the deviation angle matrix is used to provide a function model for acquiring a compensation angle; and the actual azimuth difference value Az of the antenna is obtained by scanning measurement , pitch angle difference E1;

Then Δθ satisfies:

Where Δθ and

The algorithm is based on the promotion of the Madgwick algorithm, here

For the angular angular velocity matrix,

Is the derivative of Δθ versus time; H = ωK, H is a constant coefficient, and ω is the angular velocity of the satellite;

Where Gk(rssi) is the sweep range function of the antenna, the size is determined by the antenna beam signal value rssi value; K _Az is the scan scale factor of the azimuth deviation angle, K _El is the scan scale factor of the pitch deviation angle, and the scan scale factor is It is determined by the type of antenna.

In one embodiment, the scan range function Gk(rssi) is based on the PI filter principle:

It is a constant; rssi _n and rssi _k respectively represent the collected values of the nth and kth rssi; according to the principle of the PI filter, Kp is a proportional amplification factor; Ki is an integral amplification factor;

Among them, the spiral progressive scan is performed by automatically changing the size of the scan range value Gk _n of the scan range function.

Step S400: Acquire the compensation angle according to the directivity coefficient function, the deviation angle matrix, and the Jacobian matrix, where the compensation angle is used to guide the antenna to move at a next moment.

Obtaining the compensation angle according to the directivity coefficient function, the deviation angle matrix, and the Jacobian matrix, and the compensation angle is used to guide the antenna to move at a next moment. The obtained directivity coefficient function, deviation angle matrix, and Jacobian matrix are substituted into the formula to obtain the compensation angle. Further, the following formula can be used to obtain the compensation angle:

Compensation angle

among them,

Wherein, the current time is the time n-1, where the value of Δθ _n-1 is actually measured, and the value of Δθ _n obtained from the value of Δθ _n-1 is used to guide the angle at which the antenna is to be moved at the next moment. .

Step S500: dynamically acquiring the compensation angle during the alignment process, and continuously adjusting the antenna scan tracking alignment satellite according to the compensation angle.

Specifically, in one embodiment, the compensation angle is dynamically acquired during the alignment process, and the antenna scan tracking alignment satellite is continuously adjusted according to the compensation angle. In the process of alignment, since the satellite is moving in real time, it is necessary to obtain the compensation angle in real time according to the motion of the satellite, and to adjust the azimuth difference Az and the elevation angle difference E of the antenna to further track the satellite. Among them, the spiral scanning method is adopted for the scanning method of the satellite, and the spiral progressive scanning is performed by automatically changing the scanning range value of the scanning range function.

The scan range function Gk(rssi) is based on the principle of the PI filter:

Wherein, whether the satellite is aligned is determined by a signal quality indicator of the satellite receiver. Specifically, when the received signal strength indication reaches 70% to 80%, it indicates that the antenna has been aligned with the general orientation of the satellite. When the signal quality is about 40%, it indicates that the satellite is aligned, and the signal may be eb/ The n0 value is used to determine if the satellite is aligned.

In the above embodiment, the first large-scale signal scanning is performed to make the antenna substantially face the satellite beam, and then the directional coefficient function is obtained through the darkroom simulation, and then the directional coefficient function is used to solve the partial differential function to determine the angle compensation direction and the compensation angle. The spiral progressive scan is realized by changing the scan range value, so that the antenna can realize fast tracking and alignment to the satellite, and the accuracy of the antenna beam pointing is improved; and the compensation angle of the antenna can be automatically adjusted according to different dynamic characteristics to adapt the satellite; Making full use of existing hardware resources, without adding additional equipment, reduces the dependence of tracking accuracy on servo systems and attitude inertial navigation systems.

The above-mentioned embodiments are merely illustrative of several embodiments of the present invention, and the description thereof is more specific and detailed, but is not to be construed as limiting the scope of the invention. It should be noted that a number of variations and modifications may be made by those skilled in the art without departing from the spirit and scope of the invention. Therefore, the scope of the invention should be determined by the appended claims.

Claims

A satellite tracking method for realizing fast tracking alignment of satellites, characterized in that it comprises:

Obtaining a directivity coefficient function of the antenna;

Obtaining a Jacobian matrix of the directivity coefficient function, wherein the Jacobian matrix is used to determine an angle compensation direction of the antenna;

Obtaining, by scanning, a matrix of deviation angles of the antenna relative to a satellite, the deviation angle matrix being used to provide a function model for acquiring a compensation angle;

Obtaining the compensation angle according to the directivity coefficient function, the deviation angle matrix, and the Jacobian matrix, where the compensation angle is used to guide the antenna to move at a next moment;

The compensation angle is dynamically acquired during the alignment process, and the antenna scan tracking alignment satellite is continuously adjusted according to the compensation angle.
The satellite tracking method according to claim 1, wherein the step of acquiring a directivity coefficient function of the antenna comprises:

Collecting direction coefficient data of different frequency bands of the antenna;

Converting the direction coefficient data of the different frequency bands to generate far-field direction coefficient data;

A fitting function model fitting corresponding to the antenna is selected according to the far field direction coefficient data to generate a directivity coefficient function.
The satellite tracking method according to claim 2, wherein the step of acquiring direction coefficient data of different frequency bands of the antenna comprises:

Collect the direction coefficient data of the antenna receiving band and the transmitting band.
The satellite tracking method according to claim 2, characterized in that

For a planar array antenna, the fit function model is:

Where J 1 (x) is a first-order Bessel function,
u=[Az El],

Az is the azimuth difference of the antenna obtained by the actual measurement of the antenna microwave darkroom; El is the difference of the pitch angle of the antenna obtained by the actual measurement of the antenna microwave darkroom; h is a constant, which is automatically generated by function fitting;

Substituting the azimuth difference value Az and the pitch angle difference value El into the function model to obtain a directivity coefficient function D(Az, El);

For a reflector antenna, the fit function model is:

Where J 1 (x) is a first-order Bessel function, x=u; u=[Az El];

Az is the azimuth difference of the antenna obtained by the actual measurement of the antenna microwave darkroom; El is the difference of the pitch angle of the antenna obtained by the actual measurement of the antenna microwave darkroom; h is a constant, which is automatically generated by function fitting;

Substituting the azimuth difference value Az and the pitch angle difference value E of the antenna into the function model yields a directivity coefficient function D(Az, El).
The satellite tracking method according to claim 1, wherein the step of acquiring a Jacobian matrix of the directivity coefficient function, wherein the Jacobian matrix is used to determine an angle compensation direction of the antenna comprises:

Said

among them,

Where D(Δθ n ) is another representation of D(Az, El).
The satellite tracking method according to claim 1, wherein the step of acquiring a deviation angle matrix of the antenna with respect to a satellite by scanning, the deviation angle matrix is used for providing a function model for acquiring a compensation angle, comprising:

Obtaining the actual azimuth difference value Az and the pitch angle difference value El of the antenna by scanning measurement, and setting the deviation angle matrix
Then Δθ satisfies:

among them,
For the angular angular velocity matrix,
It is the derivative of Δθ versus time; H=ωK, H is a constant coefficient; where Gk(rssi) is a function of the scan range, and the size is determined by the value of the antenna beam signal value rssi; K Az and K El are the scan scale coefficients.
The satellite tracking method according to claim 6, wherein the scan range function Gk(rssi) is based on a PI filter principle:

Is a constant; rssi n and rssi k respectively represent the collected values of the nth and kth rssi; Kp is a proportional amplification factor; Ki is an integral amplification factor;

Among them, the spiral progressive scan is performed by automatically changing the size of the scan range value of the scan range function.
The satellite tracking method according to claim 1, wherein the compensation angle is obtained according to the directivity coefficient function, the deviation angle matrix, and the Jacobian matrix, and the compensation angle is used for guiding a location The step of moving the antenna at the next moment includes:

The compensation angle

among them,

For the calculated intermediate variable; Δθ n-1 is the deviation angle matrix value at time n-1; rssi n is the collected value of the nth rssi;
It is a Jacobian matrix; D(Az, El) is the actual directivity coefficient function; Δt is the algorithm iteration period; β is the adjustment step size, and the values of different types of antennas β are different.
The satellite tracking method according to claim 1, wherein the step of dynamically acquiring the compensation angle during the alignment process and continuously adjusting the antenna scan tracking alignment satellite according to the compensation angle comprises:

And continuously adjusting the azimuth difference value Az and the pitch angle difference value of the antenna according to the compensation angle; the spiral progressive scan tracking alignment satellite;

Wherein, the spiral progressive scan is performed by automatically changing the size of the scan range value of the scan range function,

The scan range function Gk(rssi) is based on the principle of the PI filter:

Where Gk n represents the output value of the nth Gk(rssi) function, ie the scan range value; rssi max is a theoretically calculated value, which is a constant; rssi n and rssi k represent the nth and kth rssi respectively Collected value; Kp is a proportional amplification factor; Ki is an integral amplification factor;

Wherein, whether the satellite is aligned is determined by a signal quality indicator of the satellite receiver.